Control valve for fluid brakes



June 10,1941. DICKSON 2,244,942

CONTROL VALVE FOR FLUID BRAKES Filed Feb. 26', 1940 2 Sheets-Sheet 2 #1972, 455 Bess-are fun-m fm oressar INVENTOR.

ATTORNEY.

Patented June 10, 1941 UNITED STATES PATET OFFICE CONTROL VALVE FOR FLUID BRAKES James T. Dickson, Los Angeles, Calif.

Application February 26, 1940, Serial N0. 320,730

3 Claims.

My invention relates to improvements in control valves for fluid brakes, and to that type which is more particularly although not exclusively adapted for use for applying braking action to the landing wheels of air planes. supply of oil is usually provided on air planes for lubricating and other purposes and it has been common practice to maintain this liquid under heavy pressure for insuring efiicient use, by means of a suitable compressor. With my invention I have found it advantageous to employ this liquid service supply for operating the landing gear brakes to effectively control the landing of heavy loads. Due to the heavy pressure maintained in the oil supply reservoir which is usually about 600 pounds to the square inch, more or less, the application of the motivating liquid to the brakes is liable to be sudden and jerky unless some means is provided to overcome this objection. It is the primary object of my invention to provide efficient and easily controllable means for smoothly and effectively applying the motivating fluid for this purpose and entirely overcome said objection.

In the accompanying drawings forming part of this specification, Fig. 1 is a central vertical longitudinal section of my improved control valve for use in controlling the operation of landing gear and other types of vehicle brakes; Fig. 2 is a section taken on the line 2-2 of Fig. 1; Fig. 3

is a section taken on line 3-3 of Fig. 1; Fig. 4 is a schematic plan showing the application of the control valve to the landing gear brakes of an air plane; Fig. 5 is a side elevation of the control valve shown mounted upon a portion of an instrument panel or other support, and Fig. 6 is a detail showing a foot pedal attachment for operating the control valve in place of the handle shown in Fig. 5.

In the drawings, A indicates my improved control valve, B--B a pair of landing gear hydraulic brakes to which, for illustration, my improved control valve is shown applied for use, and C the oil or other fluid supply reservoir from which the actuating medium under suitable pressure is supplied for operating the brakes. Primarily the control valve A allows liquid under comparatively high compression, such as oil, to flow from. the compressed oil reservoir chamber through the brake line ducts In and II which connect with the brakes. The control valve has a cylinder l2 at one end of which is a valve chamber 13 having an egress port passage l4 coaxial with and leading into the cylinder. Threaded into said valve chamber is a valve cage l containing the A service freely movable ball check valve l6 which seats automatically by the flow of oil through port passage l4 into the cylinder. Liquid under pressure from the reservoir C enters the valve chamber through the high compression brake line duct ill and when the check valve is forced open as will be hereinafter described, enters the chamber within the cylinder. From the cylinder the brake actuating liquid flows through an egress port passage I? (see Fig. 2) into a coupling l8 and by the brake line duct II is conducted to the brakes B-B. The threaded bosses l9 and on the valve housing and cylinder are provided for mounting the control valve preferably in upright position on the instrument panel D or any other suitable support desired. A helical expansion spring 2? seated in the valve chamber [3 assists in closing the check valve "5 when the latter is released.

Arranged in the cylinder 12 is a hollow piston 2i, the head end 22 of which faces the check valve port 54 and mounted upon and coaxial with the head end of this piston is the check valve release pin 23 which is directed towards and is adapted to enter port l4 and open valve [6 when the piston is depressed. At any time that the piston 2! is released, valve l6 closes automatically by the urge of spring 21 and the pressure of liquid. from the flow line H). Any liquid under pressure contained in the chamber between the piston and the lower end of the cylinder will force the piston backwardly into normal position as shown in Fig. l, in which position an exhaust or vent port 24 in the side of the cylinder is opened and releases spent liquid from the brakes, allowing same to pass via exhaust line 25 back to the compressor 26, either to be recompressed and admitted to the supply reservoir C or conducted to any other suitable receiver. The check valve can be unseated only by the piston and when so unseated the exhaust port 24 is closed by the piston thus causing the motivating liquid under pressure to flow to the brakes through the high compression brake line duct. Under this condition the piston is subject to the full pressure which is acting upon the brakes.

To drive the piston, I provide a transverse operating shaft 3% which is journaled in a pair of bearings 3!, which in turn are threaded in the opposite sides of a suitable housing 32. This housing is formed integral with the cylinder l2 and projects from its side. One end of said shaft projects outwardly from the housing 32 and has attached thereto an operating handle 33 (see Fig. 5). Secured to the inner portion of this shaft is a crank arm 34 to the free end of which is freely pivoted by the pin 35 a spring supporting plug 36 which has an annular shoulder 31 near its pivoted end. A coil expansion spring 38 is freely threaded over said plug with one end bearing against said shoulder and its opposite end bearing against the inner closed end 22 of the hollow piston 2|. Thus when the crank arm is swung down the piston is urged under spring tension with its=.pin,23 pressingagainst, and ,whensufficient iorcejis; exerted, forcing the/check .valve open. This resilient action enables the operator to more efficiently control the check valve and;

subsequent operation of the brakes. Such contr'o under resilient application orthevawe' opefim means is particularly effective While the brake motivating liquid acts under relatively highpr'es' sure. The braking action isuw'lthin .,th'ej1operat611"s;

control and may be predetermined by, him and..- 2 any desired amount of pressure up to a mai'zimumqo may be. r ea e o ;.the a .-a e-.-- ir should-.there be an appreciable leak in th e brakes, they-pressur which snxe t d by t i o ato thr ugh the handle 33; w l: c nt ue t ac a omaticallyth u ht e o e ex ed by-.;t e p n to adijust t e:u sati tofa e c eck a ve in hehr k ne; .;.Th. .s;-res 1 -ient m an t u e n thepcheckvalve en b s .the'driv r. toiffe f thergb ak s :qr e n xo heriwo d t o. e e m 'nc; without-thought or .efiort other than that ordi nar yc r qu r d, t rnressure;:that .Will b r leasedto th b kes": The ou r e of, he-cy in- .der;=is:;c1ose -:-by a hre ded can 39 which; pro: vides; ready. access: into the cylinderanda drain duc -.401, e d ng z om the y.lin ali h ber beh nd the pist toatheexhaust; port 2.4.0 xhaust ne;-,ial1ows anyd qu d l ak ng. past the p.i.s. 2n;-=Z.; stoven soutwa d y and. prevent 1 the piston from becoming locked. 5. .Tli -,-I use;the control valve, cangbemountedion an uitab:le. supp9rh convenientrfor: use by the drivergt he threaded bosses l9 and 20 providing means-bye whi h; i bleiasteners may e; applied; joy; that; purpose. j The use of my improved valv control is not: confined togairplane landing gear it. beingpbvious that it can beused on:moordriv nizeh es o zanyikind desired; Nor is it confined for guse on; any particular numberof brakes. 4150.; when desired any. ,othermeans desired maybe applied to the shaftv301 for operating th device Qne otherof such;meansfis,shownain I which a; footpedal 4| "is connected to for-revolving; he-latterfibyfoot 111+ etead ofx an pqwerr accordance? with theipatentstatutes 'I have described r; the; principles of operation .of .my in vention together with the iapparatusawhich I now; consider to "represent the best embodiment thereof: "but I desire to: have .it "understood that the construction shown 'is'tonly; illustrative and thatathe; invention;- can be "carried out by lother means. and gappliedgto uses;ot-her thanthoseabove set-forthwithinz-the scope. of the following claims. 2.31 claim'::

:1; In .falvalveieontroll'er fora high compression 2 fiuid brake line, a check valve interposed in said line :to-r check the. flow. of fluid? therethrough, a cylinderup'onwhichsaid check valve is mounted having an ingress port passage normally-closed bysaid Valve; aspistonreciprocable' in said cylin' der having a Valve opening element on its head directed through said port passage and adapted when the piston is depressed to open said valve and allow the fiuid to circulate through the brake line and the chamber in the cylinder ahead of the piston, and said cylinder having an exhaust passage closed by the piston when the latter is depressed and opened to exhaust liquid from the chamber ahead of the piston in the cylinder received fromthe. brake line when the piston is returned and said lvalve is. released and closed, a compression spring within said cylinder and impressed against said piston adapted when subjectd to the action of compression to urge said pis- Ttoifintoia position closing said exhaust port and opening said valve, a crank arm journaled on "said"'cylinder having its free end entering the chamber inathefl'cylinder behind the piston and directed against said Spring to compress the latter-and regulate the urge of the piston and its a ve -;o n .na eleme ga ns sai iy lr a mea o ipx atin s i re an a s i lifn nbe raprovided. w th; t np ss eio fluid rom-the c amber lash. d .thwi wn, q h hausti tlead n rom t amb r in. h c l de a ad s pis e n a va v mntro ora s.ha om res$ qn f uid e u m ib ake l-i ia; a heck-:v einterr o edi saidl ne q-chs k t srfi w Q fluid there hrou a cy der. connected. with sa i z lvaa .recipma l r st nin sai cy inder hav ngazvalre openin e em nt adapted. when t'hep ton is dep e q wa dlytozopen saidrva vez-sa d piston eifis rged int en ppqs te d ecti nbyrthe presr sure o fluid moving throughthe. Valve when the latter'is open; and means-impressed against said piston. for; urging the latter ;f.or-Wa'rd1y to. adjust the, opening of. said" .va-lveyby s ai'dwalve opening element; said;cylinderphavingran exhaust; outlet from 5 the chamber ahead 710i? said, piston and a drain I passage; from ithe cylinder for. fluid. from thegchar'riberj below "said: piston to said exhaust outlet. ii. j :if: ;;;f-;.1'-:. .71.; 'I; 3;; 1.2!:

3. In a valve controller for hig-h co'rnpre'ssion fluid actuating. brake llind a check" valve interposed in saidi-lineto check-the flow of "fluid there through; "a .zcylinderi having an in'gres's passage normallyxclosed by said valv'e piston reci ro: cable in saidcylinder having aprojecting element adapted when the piston is" depresse to enter said' ingres'sipassage and open said "valve; said cylinderzhaving anexhaust passage closed by-the piston when the latter is 5 depressed andopened to exhaust fluid received from the brake" line "into the :cylinderwhen the pistofiis returned and said 'valve 'is released into closed position, a com ression"springwithin said cylinder adapted wrest: ientlyin'ge said piston'drit'oa position 'clo'sin g said exhaust passage and opening said valve, and means tending to compress said spring for urging the piston-forward 'and-applying 'said projecting elementund'er spring pressure against said valve toresilientlyfadjus't' the'latter-and' avoid sudden shock "and-jar from i the "flow"'ofilluid delivered through. the brake ling -saiu' cylinder having 1 drain passage for fluid from the cham er' bemna the piston' tof the-exhaust passage leading-from the chamber 'in: the cylinder aheadioflthe piston. 

